WASHINGTON, December 15 (Reuters) – A growing number of families in the United States are struggling to put food on the table as poverty rises in major cities, a new survey showed on Thursday.

The U.S. Conference of Mayors' 2011 hunger and homelessness survey [pdf] found all but four of the 29 cities surveyed reported an increase in requests for emergency food assistance during the period between September 2010 and August 2011.

Half of those asking for emergency food assistance were people in families, while 26 percent were employed. The elderly accounted for 19 percent, with the homeless making up the remaining 11 percent.

This is the latest survey to underscore the magnitude of the damage inflicted by the 2007-09 recession.

Though the downturn ended 2-1/2 years ago, the recovery has been very slow by historical standards as households struggle to repair their balance sheets and unemployment is at an uncomfortably high 8.6 percent.

About 24.4 million Americans are either out of work or underemployed and employment remains 6.3 million jobs below its level in December 2007 when the recession started.

According to government data, a record 49.1 million Americans were living in poverty in 2010.

During that period, the number of households depending on food stamps - subsidies that help people cover the costs of groceries - soared 16 percent to 13.6 million.

The mayors' survey attributed unemployment, poverty, low wages, and high housing costs as the main reasons behind the surge in demand for food assistance.

It found there was a 10 percent average increase in the amount of food being distributed by the cities and just over two-thirds of the cities reported a rise in the quantities they were handing out.

About 71 percent of cities said their total budget for emergency food purchases had gone up. Across the 29 cities, 27 percent of the people requiring emergency food assistance did not receive it, the survey found.

In 86 percent of the cities, food pantries and emergency kitchens had to reduce the quantities of food people could receive per visit or the amount of food offered per meal.

None of the cities expected demand for food assistance to decline over the next year. Many anticipated a drop in the resources to provide food assistance, citing cuts in government funding and declining food donations by the public.

The survey also found that homelessness increased by an average of six percent across the 29 cities.